JP4788591B2 - Visible light control device, visible light communication device, visible light control method and program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a visible light control apparatus capable of adjusting the brightness of the visible light to arbitrary brightness. <P>SOLUTION: The visible light control apparatus comprises a modulation means äequivalent to a PPM signal generation circuit (1), a subcarrier generation circuit (2), and a first AND circuit (4)} that modulates the subcarrier to form a modulation signal, a visible light control means äequivalent to a drive circuit (8)} that controls turning on and off of the visible light, which includes information, based on the modulation signal modulated by the modulation means (1, 2, 4) to make the visible light emitted with a predetermined light emission time ratio, and a light emission time ratio control means äequivalent to a brightness control signal generating circuit (3), an inversion circuit (5), a second AND circuit (6), and an OR circuit (7)} that varies the predetermined light emission time ratio to emit the visible light with a varied light emission time ratio. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

The present invention, visible light control device for controlling the flashing of the light (visible light) visible to the human eye, its visible light control apparatus visible light communication apparatus for communicating information using visible light controlled by the visible light control apparatus The present invention relates to a visible light control method and program .

  Conventionally, when performing information communication, infrared rays that are invisible to human eyes have been applied. The reason is that infrared rays have higher transmission efficiency than visible light, and visible light may be visually uncomfortable or disturbing for humans.

  However, since visible light allows a person to visually recognize a visible light receivable region, depending on the application, it may be more convenient and more entertaining than infrared light. In addition, since visible light is a kind of the same wave as a radio wave, it is naturally possible to transmit information.

  For this reason, as a technical literature filed prior to the present invention, a position data unit that generates position information, a modulation unit that modulates an electric signal on a power line based on position information from the position data unit, and a position There is a document that discloses a position information communication device that includes an illumination unit that generates illumination light using an electrical signal modulated by information and communicates position information using optical wireless communication using illumination light (visible light) (For example, refer to Patent Document 1).

  Further, there is a document describing the possibility of visible light communication (for example, see Non-Patent Document 1).

Note that visible light has important characteristics. Its characteristic is that it blinks rapidly. Various information can be transmitted by blinking the visible light at a high speed that cannot be felt by human eyes. For this reason, by performing information communication using visible light, it overcomes various problems caused by wireless communication and infrared communication, and is ubiquitous, extremely fast, and affects human bodies and electronic devices. No communication is possible.
JP 2005-218066 A Nakagawa Masao, Yukibitas Visible Light Communication, IEICE Transactions, IEICE 2005, B Vol. J-88-B No.2 pp. 351-359

  As a visible light communication method, the subcarrier is modulated, the modulated signals shown in FIGS. 1A and 1B are generated, and the blinking of visible light is controlled based on the generated modulated signals. The main communication method is to emit visible light at a predetermined light emission time ratio and transmit visible light including information. FIG. 1 (a) shows a modulation signal for emitting visible light at a light emission time ratio of 12.5%. When the modulation signal is 1, a carrier wave signal is generated and the visible light is turned on. When the modulation signal is 0, the visible light is turned off. FIG. 1B shows a modulation signal obtained by inverting the modulation signal shown in FIG. 1A, and shows a modulation signal when emitting visible light at a light emission time ratio of 87.5%. When the modulation signal is 1, the carrier wave signal is generated and the visible light is turned on. When the modulation signal is 0, the visible light is turned off. Note that the modulation signal shown in FIG. 1B has longer time to illuminate the visible light than the modulation signal shown in FIG. 1A, so that brighter visible light can be emitted for the same peak current. It becomes possible.

  In the communication method described above, as shown in FIGS. 1A and 1B, the light emission time ratio is fixed at 12.5% or 87.5%, and the brightness of visible light is arbitrary. The brightness cannot be adjusted. For this reason, it is desired to be able to adjust the brightness of visible light to an arbitrary brightness. However, although Patent Document 1 and Non-Patent Document 1 disclose the point of emitting visible light including information, the brightness of visible light is changed by changing the emission time ratio for emitting the visible light. There is no consideration about adjusting the brightness to an arbitrary brightness.

The present invention has been made in view of the above circumstances, and provides a visible light control device , a visible light communication device , a visible light control method, and a program capable of adjusting the brightness of visible light to an arbitrary brightness. It is intended to do.

  In order to achieve this object, the present invention has the following features.

The visible light control device according to the present invention is
Based on the modulation means that modulates the subcarrier and generates a modulation signal, and the modulation signal generated by the modulation means, the blinking of visible light including information is controlled, and the visible light is emitted at a predetermined emission time ratio. A visible light control device having a visible light control means,
A light emission time ratio control means for changing the predetermined light emission time ratio and emitting the visible light at the changed light emission time ratio;
The light emission time ratio control means includes:
Periodic modulation signal generation means for generating a periodic modulation signal for changing the period of the modulation signal generated by the modulation means;
Drive signal generation means for generating a drive signal that is a logical sum of the period modulation signal generated by the period modulation signal generation means and the modulation signal generated by the modulation means;
Based on the drive signal generated by the drive signal generation means, the blinking of the visible light is controlled, the predetermined light emission time ratio is changed, and the visible light is emitted at the changed light emission time ratio. And

The visible light communication device according to the present invention is
  A visible light communication device equipped with the visible light control device described above, wherein the visible light control device controls the blinking of visible light emitted from an optical element and transmits the visible light. .

The visible light control method according to the present invention includes:
A visible light control method performed by a visible light control device that controls blinking of visible light including information,
A modulation step of modulating the subcarrier and generating a modulated signal;
Based on the modulation signal generated by the modulation step, the visible light control step of controlling the blinking of the visible light and emitting the visible light at a predetermined light emission time ratio;
The visible light control device performs the light emission time ratio control step of changing the predetermined light emission time ratio and emitting the visible light at the changed light emission time ratio,
The light emission time ratio control step includes:
A period modulation signal generation step for generating a period modulation signal for changing the period of the modulation signal generated by the modulation step;
A drive signal generation step of generating a drive signal that is a logical sum of the periodic modulation signal generated by the periodic modulation signal generation step and the modulation signal generated by the modulation step;
Based on the drive signal generated by the drive signal generation step, the blinking of the visible light is controlled, the predetermined light emission time ratio is changed, and the visible light is emitted at the changed light emission time ratio. And

The program according to the present invention is:
A program to be executed by a computer of a visible light control device that controls blinking of visible light including information,
Modulation processing for modulating a subcarrier and generating a modulated signal;
Based on the modulation signal generated by the modulation process, the visible light control process for controlling the blinking of the visible light and emitting the visible light at a predetermined emission time ratio;
Changing the predetermined light emission time ratio, and causing the computer to execute a light emission time ratio control process for emitting the visible light at the changed light emission time ratio,
The light emission time ratio control process is:
A period modulation signal generation process for generating a period modulation signal for changing the period of the modulation signal generated by the modulation process;
A drive signal generation process for generating a drive signal that is a logical sum of the period modulation signal generated by the period modulation signal generation process and the modulation signal generated by the modulation process;
Based on the drive signal generated by the drive signal generation process, the blinking of the visible light is controlled, the predetermined light emission time ratio is changed, and the visible light is emitted at the changed light emission time ratio. And

  According to the present invention, it is possible to adjust visible light to an arbitrary brightness by changing a predetermined light emission time ratio and emitting visible light at the changed light emission time ratio.

  First, the features of the visible light control device and the visible light control circuit in this embodiment will be described with reference to FIG.

  The visible light control device according to this embodiment corresponds to a modulation means “PPM signal generation circuit (1), subcarrier generation circuit (2), and first AND circuit (4) that modulates a subcarrier and generates a modulation signal. ”And the visible light control means for controlling the blinking of visible light including information based on the modulation signal modulated by the modulation means (1, 2, 4) and emitting visible light at a predetermined light emission time ratio. Equivalent to the circuit (8) ”, a light emission time ratio control means for changing the predetermined light emission time ratio and emitting visible light at the changed light emission time ratio. It corresponds to a generation circuit (3), an inverting circuit (5), a second AND circuit (6), and an OR circuit (7) ”. Thereby, it becomes possible to adjust visible light to arbitrary brightness.

  The visible light control circuit according to the present embodiment modulates a subcarrier and generates a modulation signal “PPM signal generation circuit (1), subcarrier generation circuit (2), first AND circuit (4)”. ”And controls the blinking of visible light emitted from the optical element (9) based on the modulation signal generated by the modulation circuit (1, 2, 4), and the optical element (9) at a predetermined emission time ratio. And a drive circuit (8) for emitting visible light from the light control signal generating circuit “light control signal generation circuit for generating a light control signal for changing a predetermined light emission time ratio by the modulation signal” Equivalent to the signal generation circuit (3) ”and driving with the period of the modulation signal generated by the modulation circuit (1, 2, 4) changed based on the dimming signal generated by the dimming signal generation circuit (3) Drive signal generation circuit for generating a signal “inverting circuit (5 , Corresponding to the second AND circuit (6) and OR circuit (7) ”, and the drive circuit (8) is based on the drive signal generated by the drive signal generation circuit (5, 6, 7). In addition, by controlling blinking of visible light emitted from the optical element (9), visible light is emitted from the optical element (9) at a light emission time ratio obtained by changing a predetermined light emission time ratio by a modulation signal. It is what. Thereby, it becomes possible to adjust visible light to arbitrary brightness. Hereinafter, the visible light control device (visible light control circuit) in the present embodiment will be described with reference to the accompanying drawings.

(First embodiment)
First, the configuration of the visible light control device of this embodiment will be described with reference to FIG.

  The visible light control device according to the present embodiment includes a PPM (Pulse Position Modulation) signal generation circuit (1), a subcarrier generation circuit (2), a dimming signal generation circuit (3), and a first AND circuit (4 ), An inverting circuit (5), a second AND circuit (6), an OR circuit (7), a drive circuit (8), and an optical element (9).

  The PPM signal generation circuit (1) is a circuit for outputting a PPM signal, converts a digital main signal into a PPM signal at a rate of one per frame determined by a frame signal, and outputs the converted PPM signal. Will do.

  Note that the conversion (modulation) from the main signal to the PPM signal performed by the PPM signal generation circuit (1) converts, for example, the main signal into the PPM signal at a rate of one per frame. When the PPM signal generation circuit (1) performs quaternary position modulation, as shown in FIG. 3, when the main signal is “00”, the PPM signal is “1000” and “01”. In this case, “0100” is obtained, “10” is designated “0010”, and “11” is designated “0001”. In the case of this four-value position modulation, the mark rate within one frame of the PPM signal is 1/4. Note that the position modulation performed by the PPM signal generation circuit (1) is not limited to quaternary position modulation, and multi-level position modulation such as binary can also be performed.

  The subcarrier generation circuit (2) is a circuit for outputting a subcarrier. The dimming signal generation circuit (3) is a circuit for outputting a dimming signal for changing the light emission time ratio of visible light.

  The first AND circuit (4) synthesizes the PPM signal output from the PPM signal generation circuit (1) and the subcarrier output from the subcarrier generation circuit (2) at a predetermined light emission time ratio. A modulation signal for causing the optical element (9) to emit light is generated and output. Since the average power of the modulation signal generated in the first AND circuit (4) is constant, the brightness of the visible light when the optical element (9) emits light based on this modulation signal is visible. Regardless of the contents of the information to be transmitted in the light, it becomes constant and flickering of visible light can be prevented.

  The inverting circuit (5) generates and outputs an inverted PPM signal obtained by inverting the PPM signal output from the PPM signal generating circuit (1).

  The second AND circuit (6) combines the inverted PPM signal output from the inversion circuit (5) and the dimming signal output from the dimming signal generation circuit (3), and the first AND circuit. A periodic modulation signal for changing the period of the modulation signal output from (4) is generated and output.

  The OR circuit (7) synthesizes the modulation signal output from the first AND circuit (4) and the periodic modulation signal output from the second AND circuit (6), and drives the drive circuit (8). A drive signal for control is generated and output.

  The drive circuit (8) controls blinking of the optical element (9) based on the drive signal output from the OR circuit (7), and emits visible light at a light emission time ratio according to the drive signal.

  The optical element (9) emits visible light, and emits visible light of arbitrary brightness under the control of the drive circuit (8). The optical element (9) is not particularly limited as long as it emits visible light, and an LD (Laser Diode), an LED (Light Emitting Diode), or the like is applicable.

  Next, the control operation in the visible light control device shown in FIG. 2 will be described with reference to FIG. FIG. 4 is a diagram showing signals output from each circuit constituting the visible light control device shown in FIG.

  First, the PPM signal generation circuit (1) outputs the PPM signal shown in FIG. 4A, and the subcarrier generation circuit (2) outputs the subcarrier shown in FIG. 4B. Next, the first AND circuit (4) outputs the PPM signal shown in FIG. 4 (a) output from the PPM signal generation circuit (1) and FIG. 4 (b) output from the subcarrier generation circuit (2). 4), the modulation signal shown in FIG. 4C, which is the logical product of (a) the PPM signal and (b) the subcarrier, is generated, and the generated modulation signal is output. To do.

  Further, the inverting circuit (5) inverts the PPM signal shown in FIG. 4 (a) output from the PPM signal generating circuit (1) to generate the inverted PPM signal shown in FIG. 4 (d). An inverted PPM signal is output.

  The second AND circuit (6) is shown in FIG. 4 (e) output from the inverted PPM signal shown in FIG. 4 (d) output from the inverter circuit (5) and the dimming signal generation circuit (3). Based on the dimming signal, the periodic modulation signal shown in FIG. 4F, which is the logical product of (d) the inverted PPM signal and (e) the dimming signal, is generated, and the generated periodic modulation signal Is output.

  The OR circuit (7) outputs the modulation signal shown in FIG. 4C output from the first AND circuit (4) and the period shown in FIG. 4F output from the second AND circuit (6). Based on the modulation signal, the drive signal shown in FIG. 4G that is the logical sum of (c) the modulation signal and (f) the periodic modulation signal is generated, and the generated drive signal is output.

  The drive circuit (8) controls the blinking of the optical element (9) based on the drive signal shown in FIG. 4 (g) output from the OR circuit (7), and the drive signal shown in FIG. 4 (g). Visible light is emitted from the optical element (9) at a light emission time ratio according to, and visible light including arbitrary information is transmitted.

  Thus, the visible light control device according to the present embodiment changes the period of the modulation signal shown in FIG. 4C based on the dimming signal shown in FIG. 4E for changing the light emission time ratio. 4 (g) is generated, and on the basis of the generated drive signal, the drive circuit (8) controls the blinking of the optical element (9), whereby the modulation shown in FIG. The light emission time ratio of the signal is changed, and visible light is emitted at the changed light emission time ratio of the drive signal shown in FIG. Thereby, it is possible to adjust the visible light emitted from the optical element (9) to an arbitrary brightness, and to transmit visible light including information with the adjusted arbitrary brightness.

  It should be noted that the duty ratio of the dimming signal shown in FIG. 4 (e) output from the dimming signal generation circuit (3) shown in FIG. 2 is adjusted to be “1” than the dimming signal shown in FIG. 4 (e). When the dimming signal shown in FIG. 5 (e) having a high ratio is output from the dimming signal generation circuit (3), the second AND circuit (6) uses the periodic modulation signal shown in FIG. 4 (f). 5 (f) having a high ratio of “1” is output, and an OR circuit (7) for outputting a drive signal based on the periodic modulation signal is shown in FIG. 4 (g). The drive signal shown in FIG. 5G having a higher ratio of “1” than the shown drive signal is output. Accordingly, the drive circuit (8) controls the blinking of the optical element (9) based on the drive signal shown in FIG. 5 (g) having a high ratio of “1” output from the OR circuit (7). Visible light is emitted at the light emission time ratio of the drive signal shown in FIG. 5 (g) having a high ratio of “1”, and the drive circuit (8) is more than the drive signal shown in FIG. 4 (g). Bright “visible light” is emitted and visible light containing information is transmitted. Therefore, the duty ratio of the dimming signal output from the dimming signal generation circuit (3) is adjusted, a driving signal is generated based on the adjusted dimming signal, and driving is performed based on the generated driving signal. By controlling the blinking of the optical element (9) in the circuit (8), it is possible to change the light emission time ratio of visible light emitted from the optical element (9).

(Second Embodiment)
Next, a second embodiment will be described.

  As shown in FIG. 6, the visible light control device in the second embodiment includes a PPM signal generation circuit (1) that outputs a PPM signal that constitutes the visible light control device of the first embodiment shown in FIG. An inverted PPM signal generation circuit (10) that outputs an inverted PPM signal obtained by inverting the PPM signal is provided. This makes it possible to change the light emission time ratio of the optical element (9) and adjust the visible light emitted from the optical element (9) to an arbitrary brightness as in the visible light control device of the first embodiment. It becomes. Hereinafter, the visible light control apparatus according to the second embodiment will be described with reference to FIGS. 6 and 7.

  First, the configuration of the visible light control device according to the second embodiment will be described with reference to FIG.

  The visible light control device according to the second embodiment causes the PPM signal generation circuit (1) constituting the visible light control device according to the first embodiment shown in FIG. 2 to invert the PPM signal as shown in FIG. The inverted PPM signal generation circuit (10) that outputs the inverted PPM signal is used.

  Next, the control operation in the visible light control apparatus of the second embodiment shown in FIG. 6 will be described with reference to FIG. FIG. 7 is a diagram illustrating signals output from each circuit constituting the visible light control device illustrated in FIG. 6.

  First, the inverted PPM signal generation circuit (10) outputs the inverted PPM signal shown in FIG. 7A, and the subcarrier generation circuit (2) outputs the subcarrier shown in FIG. 7B. Next, the first AND circuit (4) outputs the inverted PPM signal shown in FIG. 7A output from the inverted PPM signal generation circuit (10) and the output from the subcarrier generation circuit (2). Based on the subcarriers shown in (b), the modulation signal shown in FIG. 7C, which is the logical product of (a) the inverted PPM signal and (b) the subcarrier, is generated, and the generated modulation is generated. Output a signal.

  Further, the inverting circuit (5) inverts the inverted PPM signal shown in FIG. 7 (a) output from the inverted PPM signal generating circuit (10) to generate the PPM signal shown in FIG. 7 (d). Output the PPM signal.

  The second AND circuit (6) includes the PPM signal shown in FIG. 7 (d) output from the inverting circuit (5) and the dimming shown in FIG. 7 (e) output from the dimming signal generation circuit (3). Based on the optical signal, the periodic modulation signal shown in FIG. 7F, which is the logical product of (d) the PPM signal and (e) the dimming signal, is generated, and the generated periodic modulation signal is output. To do.

  The OR circuit (7) outputs the modulation signal shown in FIG. 7C output from the first AND circuit (4) and the period shown in FIG. 7F output from the second AND circuit (6). Based on the modulation signal, the drive signal shown in FIG. 7G that is the logical sum of (c) the modulation signal and (f) the periodic modulation signal is generated, and the generated drive signal is output.

  The drive circuit (8) controls blinking of the optical element (9) based on the drive signal shown in FIG. 7 (g) output from the OR circuit (7), and the optical element at the light emission time ratio according to the drive signal. Visible light is emitted from (9), and visible light including arbitrary information is transmitted.

  As described above, the visible light control device according to the second embodiment is based on the dimming signal shown in FIG. 7E for changing the light emission time ratio, similarly to the visible light control device according to the first embodiment. In addition, the drive signal shown in FIG. 7G in which the period of the modulation signal shown in FIG. 7C is changed is generated, and the optical element (9) is generated in the drive circuit (8) based on the generated drive signal. By controlling the blinking of the light, it is possible to change the light emission time ratio of the modulation signal shown in FIG. 7C, and to emit visible light at the light emission time ratio of the drive signal shown in FIG. It becomes possible. Thereby, it is possible to adjust the visible light emitted from the optical element (9) to an arbitrary brightness, and to transmit visible light including information with the adjusted arbitrary brightness.

(Third embodiment)
Next, a third embodiment will be described.

  As shown in FIG. 8, the visible light control apparatus according to the third embodiment is provided with a PPM signal / inverted PPM signal generation circuit (11) for outputting a PPM signal or an inverted PPM signal. It is. As a result, the PPM signal or the inverted PPM signal is output from the PPM signal / inverted PPM signal generation circuit (11), and the visible light control device in the first embodiment or the visible light control device in the second embodiment. It is possible to perform a control operation similar to the above. Hereinafter, the visible light control apparatus according to the third embodiment will be described with reference to FIGS. 8 and 9.

  First, the configuration of the visible light control device according to the third embodiment will be described with reference to FIG.

  The visible light control device according to the third embodiment is a PPM signal generation circuit (1) constituting the visible light control device according to the first embodiment shown in FIG. 2, or the visible light control device according to the second embodiment shown in FIG. The inverted PPM signal generation circuit (10) constituting the light control device is replaced with a PPM signal or an inverted PPM signal generation circuit (11) that outputs an inverted PPM signal. As a result, the PPM signal or the inverted PPM signal is output from the PPM signal / inverted PPM signal generation circuit (11).

  Next, the internal configuration of the PPM signal / inverted PPM signal generation circuit (11) shown in FIG. 8 will be described with reference to FIG.

  The PPM signal / inverted PPM signal generation circuit (11) includes a PPM modulation circuit (101), an inversion circuit (102), a changeover switch (103), and a switch control circuit (104). .

  A PPM modulation circuit (101) converts a digital main signal into a PPM signal at a rate of one per frame determined by a frame signal, and outputs the converted PPM signal.

  The inverting circuit (102) inverts the PPM signal output from the PPM modulation circuit (101) and outputs an inverted PPM signal.

  The changeover switch (103) switches to either the PPM signal output from the PPM modulation circuit (101) or the inverted PPM signal output from the inverting circuit (102), and the PPM signal / inverted PPM signal generation circuit The signal to be output from (11) is selected. The changeover switch (103) is switched based on a control signal output from the switch control circuit (104) to switch the changeover switch (103) and output from the PPM signal / inverted PPM signal generation circuit (11). Will be selected.

  As described above, the visible light control device according to the third embodiment switches the PPM signal or the inverted PPM signal by the changeover switch (103) and outputs the PPM signal / inverted PPM signal generation circuit (11). It is possible to perform the same control operation as the visible light control device in the first embodiment or the visible light control device in the second embodiment.

(Fourth embodiment)
Next, a fourth embodiment will be described.

  The visible light control device according to the fourth embodiment relaxes the rate of time change at the change point of the drive signal output from the OR circuit (7) constituting the visible light communication device according to the first to third embodiments described above. Then, visible light is emitted from the optical element (9) at the light emission time ratio of the relaxed drive signal. Thus, as in the visible light control devices in the first to third embodiments, the predetermined light emission time ratio is changed, visible light is emitted at the changed light emission time ratio, and light is emitted from the optical element (9). Even when the visible light to be controlled is adjusted to an arbitrary brightness, as shown in FIG. 10, noise having a frequency component lower than the modulation signal “modulation signal spectrum” output from the first AND circuit (4) Since only a “noise spectrum” is generated, even if information is transmitted with visible light adjusted to an arbitrary brightness, a transmission error does not occur, and highly accurate information communication can be performed. Hereinafter, the visible light control apparatus according to the fourth embodiment will be described with reference to FIGS.

  First, the configuration of the visible light control device according to the fourth embodiment will be described with reference to FIG.

  As shown in FIG. 11, the visible light control device according to the fourth embodiment includes a variable time constant circuit (20) for reducing the rate of time change at the change point of the drive signal output from the OR circuit (7). It is provided. As a result, the rate of time change at the change point of the drive signal output from the OR circuit (7) can be relaxed, and the drive circuit (8) can relax the relaxed drive signal relaxed in the variable time constant circuit (20). The light emission time ratio of the relaxed drive signal in which the time change rate at the change point of the light emission time ratio of the drive signal output from the OR circuit (7) is relaxed by controlling the blinking of the optical element (9) based on Thus, visible light can be emitted from the optical element (9).

  Next, the internal configuration of the variable time constant circuit (20) shown in FIG. 11 will be described with reference to FIG.

  The variable time constant circuit (20) includes an analog switch (201), a resistor R (202), and a capacitor C (203).

  The variable time constant circuit (20) shown in FIG. 12 performs on / off switching control of the analog switch (201) on the basis of the PPM signal output from the PPM signal generation circuit (1), and the PPM signal generation circuit ( When the PPM signal output from 1) is “1”, the analog switch (201) is turned on. When the PPM signal is “0”, the analog switch (201) is turned off, and the analog switch (201) is turned on. ) Is turned on / off, the time change rate at the changing point of the drive signal output from the OR circuit (7) is relaxed, and the relaxed relaxed drive signal is output.

  When the analog switch (201) is off, an output from the OR circuit (7) has a large time constant determined by the resistance value of the resistor (202): R and the capacitance of the capacitor (203): C. When the analog switch (201) is turned on, the resistance value: R becomes smaller when the analog switch (201) is on, so that the time constant is smaller than when the analog switch (201) is off. Thus, the rate of time change at the change point of the drive signal output from the OR circuit (7) is relaxed.

  Next, a control operation in the visible light control apparatus of the fourth embodiment shown in FIG. 11 will be described with reference to FIG. FIG. 13 is a diagram illustrating signals output from each circuit constituting the visible light control device illustrated in FIG. 11.

  In the visible light control device of the fourth embodiment, the control operation until the drive signal shown in FIG. 13G is output from the OR circuit (7) is the same control as that of the visible light control device of the first embodiment. Will perform the action. The variable time constant circuit (20) switches on / off of the analog switch (201) shown in FIG. 12 based on the PPM signal shown in FIG. 13 (a) output from the PPM signal generation circuit (1). The time change rate at the change point of the drive signal shown in FIG. 13 (g) output from the OR circuit (7) is relaxed with a time constant determined by turning on and off the analog switch (201). The relaxation drive signal shown in (h) is generated and output. Then, the drive circuit (8) controls the blinking of the optical element (9) based on the relaxation drive signal shown in FIG. 13 (h) output from the variable time constant circuit (20), and based on the relaxation drive signal. Visible light is emitted from the optical element (9) at a light emission time ratio, and visible light including arbitrary information is transmitted.

  As described above, in the visible light control device according to the fourth embodiment shown in FIG. 11, the variable time constant circuit (20) is based on the PPM signal output from the PPM signal generation circuit (1), and the OR circuit (7 13), the time change rate at the change point of the drive signal shown in FIG. 13 (g) is relaxed to generate the relaxed drive signal shown in FIG. 13 (h), and the drive is performed based on the generated relaxed drive signal. By controlling the blinking of the optical element (9) in the circuit (8), the temporal drive rate at the change point of the drive signal shown in FIG. Visible light is emitted at a time ratio. Thus, even when the visible light emitted from the optical element (9) is controlled to be adjusted to an arbitrary brightness, the modulation signal “modulation” output from the first AND circuit (4) as shown in FIG. Only noise (noise spectrum) with a frequency component lower than the “signal spectrum” is generated, so even if information is transmitted with visible light adjusted to an arbitrary brightness, no transmission error occurs, and highly accurate information communication is performed. Is possible.

  Note that the visible light control device of the fourth embodiment shown in FIG. 11 described above has a configuration in which a variable time constant circuit (20) is provided with respect to the visible light control device of the first embodiment shown in FIG. However, the variable time constant circuit (20) described above is also provided for the visible light control device of the second embodiment shown in FIG. 6 and the visible light control device of the third embodiment shown in FIG. 14 and the configuration shown in FIG. 15, and the control operation described above is performed.

  FIG. 14 shows a configuration in which a variable time constant circuit (20) is provided in the visible light control device of the second embodiment shown in FIG. In the visible light control device shown in FIG. 14, the variable time constant circuit (20) is driven by the OR circuit (7) based on the inverted PPM signal output from the inverted PPM signal generation circuit (10). A relaxation drive signal in which the rate of time change at the change point is relaxed is generated, and the generated relaxation drive signal is output to the drive circuit (8).

  FIG. 15 shows a configuration in which a variable time constant circuit (20) is provided in the visible light control device of the third embodiment shown in FIG. In the visible light control device shown in FIG. 15, the variable time constant circuit (20) has an OR circuit (20) based on the PPM signal or the inverted PPM signal output from the PPM signal / inverted PPM signal generating circuit (10). The relaxed drive signal in which the rate of time change at the change point of the drive signal output from 7) is relaxed is generated, and the generated relaxed drive signal is output to the drive circuit (8).

  As described above, the visible light control device according to the fourth embodiment relaxes the rate of time change at the change point of the drive signal output from the OR circuit (7) based on the PPM signal or the inverted PPM signal. Even when the visible light is adjusted to an arbitrary brightness by generating a relaxation driving signal and causing visible light to be emitted from the optical element (9) at the emission time ratio of the generated relaxation driving signal, as shown in FIG. In addition, since only noise “noise spectrum” having a frequency component lower than that of the modulation signal “modulation signal spectrum” output from the first AND circuit (4) is generated, information is transmitted with visible light adjusted to an arbitrary brightness. However, a transmission error does not occur, and highly accurate information communication can be performed.

  The above-described embodiment is a preferred embodiment of the present invention, and the scope of the present invention is not limited to the above-described embodiment alone, and various modifications are made without departing from the gist of the present invention. Implementation is possible. For example, by mounting the visible light control device (visible light control circuit) of the above-described embodiment on a visible light communication device that performs information communication using visible light, the mounted visible light control device (visible light) Information communication can be performed based on visible light adjusted to an arbitrary brightness by a control circuit.

  In addition, the control operation in the above-described visible light control device (visible light control circuit) of the present embodiment can be executed not by hardware but by software such as a computer program. By recording on a recording medium such as a recording medium, a magnetic recording medium, a magneto-optical recording medium, or a semiconductor, and reading the program from the recording medium into an electronic device having the optical element (9), the above-described control operation is performed. It can also be executed in an electronic device having the optical element (9). Further, the above-described control operation is executed in the electronic device having the optical element (9) by causing the electronic device having the optical element (9) to read the program from an external device connected via a predetermined network. It is also possible to make it.

The present invention is applicable to an electronic device having an optical element (9).

It is a figure which shows the modulation signal by which the light emission time ratio was fixed to 12.5% or 87.5%. It is a figure which shows the structure of the visible light control apparatus (visible light control circuit) in 1st Embodiment. It is a figure for demonstrating the position modulation performed with a PPM signal generation circuit (1). FIG. 3 is a first diagram illustrating a signal output from each circuit constituting the visible light control device (visible light control circuit) of the first embodiment illustrated in FIG. 2. It is the 2nd figure showing the signal outputted from each circuit which constitutes the visible light control device (visible light control circuit) of a 1st embodiment shown in Drawing 2, and it outputs from a dimming signal generation circuit (3) It is a figure which shows the case where the duty ratio of a light control signal is adjusted and the light control signal with a high ratio of "1" is output. It is a figure which shows the structure of the visible light control apparatus (visible light control circuit) in 2nd Embodiment. It is a figure which shows the signal output from each circuit which comprises the visible light control apparatus (visible light control circuit) of 2nd Embodiment shown in FIG. It is a figure which shows the structure of the visible light control apparatus (visible light control circuit) in 3rd Embodiment. It is a figure which shows the internal structure of the PPM signal / inversion PPM signal generation circuit (11) which comprises the visible light control apparatus (visible light control circuit) of 3rd Embodiment. It is a figure which shows the state of the "noise (noise)" generate | occur | produced when the visible light control apparatus (visible light control circuit) in 4th Embodiment adjusts visible light to arbitrary brightness. It is a 1st figure which shows the structure of the visible light control apparatus (visible light control circuit) in 4th Embodiment. It is a figure which shows the internal structural example of the variable time constant circuit (20) which comprises the visible light control apparatus (visible light control circuit) of 4th Embodiment. It is a figure which shows the signal output from each circuit which comprises the visible light control apparatus (visible light control circuit) of 4th Embodiment shown in FIG. It is a 2nd figure which shows the structure of the visible light control apparatus (visible light control circuit) in 4th Embodiment. It is a 3rd figure which shows the structure of the visible light control apparatus (visible light control circuit) in 4th Embodiment.

Explanation of symbols

1 PPM signal generation circuit (signal conversion means)
2 Subcarrier generation circuit (subcarrier)
3 Dimming signal generating circuit (dimming signal generating means, adjusting means)
4 1st AND circuit (modulation means)
5 Inverting circuit 6 Second AND circuit (periodic modulation signal generating means)
7 OR circuit (drive signal generating means)
8 Drive circuit (visible light control means)
9 Optical element 10 Inverted PPM signal generation circuit (signal conversion means)
11 PPM signal / inverted PPM signal generation circuit (signal conversion means)
101 PPM modulation circuit 102 Inversion circuit 103 Changeover switch (signal selection means)
104 Switch control circuit (signal selection means)
20 Variable time constant circuit (light emission time ratio relaxation control means)
201 Analog switch 202 Resistance R
203 Capacitor C

Claims (12)

Based on the modulation means that modulates the subcarrier and generates a modulation signal, and the modulation signal generated by the modulation means, the blinking of visible light including information is controlled, and the visible light is emitted at a predetermined emission time ratio. A visible light control device having a visible light control means,
A light emission time ratio control means for changing the predetermined light emission time ratio and emitting the visible light at the changed light emission time ratio;
The light emission time ratio control means includes:
Periodic modulation signal generation means for generating a periodic modulation signal for changing the period of the modulation signal generated by the modulation means;
Drive signal generation means for generating a drive signal that is a logical sum of the period modulation signal generated by the period modulation signal generation means and the modulation signal generated by the modulation means;
Based on the drive signal generated by the drive signal generation means, the blinking of the visible light is controlled, the predetermined light emission time ratio is changed, and the visible light is emitted at the changed light emission time ratio. Visible light control device.   And a light emission time ratio relaxation control unit that relaxes a time change rate at a change point of the drive signal generated by the drive signal generation unit and emits the visible light at a light emission time ratio of the relaxed drive signal. The visible light control device according to claim 1. The modulating means includes
Signal conversion means for converting the main signal into a multi-level PPM (Pulse Position Modulation) signal or an inverted multi-level PPM signal obtained by inverting the multi-level PPM signal;
3. The visible signal according to claim 1, wherein the modulated signal is generated by modulating the subcarrier based on the multilevel PPM signal or the inverted multilevel PPM signal converted by the signal conversion means. Light control device. The periodic modulation signal generating means includes
A dimming signal generating means for generating a dimming signal for changing the predetermined light emission time ratio;
Synthesis means for synthesizing the dimming signal generated by the dimming signal generation means and the multilevel PPM signal converted by the signal conversion means or the inverted multilevel PPM signal;
The visible light control device according to claim 3, further comprising: The dimming signal generating means includes
Adjusting means for adjusting the duty ratio of the dimming signal;
The visible light control device according to claim 4, wherein the light control signal having a duty ratio adjusted by the adjusting unit is generated. The light emission time ratio relaxation control means includes:
The time change rate at the change point of the drive signal generated by the drive signal generation unit is reduced based on the multilevel PPM signal converted by the signal conversion unit or the inverted multilevel PPM signal. Item 6. The visible light control device according to Item 3.   7. The signal selection unit according to claim 3, further comprising: a signal selection unit that selects either the multilevel PPM signal converted by the signal conversion unit or the inverted multilevel PPM signal. 8. Visible light control device.   A visible light communication device equipped with the visible light control device according to any one of claims 1 to 7, wherein the visible light control device controls flashing of visible light emitted from an optical element, and A visible light communication apparatus that transmits visible light. A visible light control method performed by a visible light control device that controls blinking of visible light including information,
A modulation step of modulating the subcarrier and generating a modulated signal;
Based on the modulation signal generated by the modulation step, the visible light control step of controlling the blinking of the visible light and emitting the visible light at a predetermined light emission time ratio;
The visible light control device performs the light emission time ratio control step of changing the predetermined light emission time ratio and emitting the visible light at the changed light emission time ratio,
The light emission time ratio control step includes:
A period modulation signal generation step for generating a period modulation signal for changing the period of the modulation signal generated by the modulation step;
A drive signal generation step of generating a drive signal that is a logical sum of the periodic modulation signal generated by the periodic modulation signal generation step and the modulation signal generated by the modulation step;
Based on the drive signal generated by the drive signal generation step, the blinking of the visible light is controlled, the predetermined light emission time ratio is changed, and the visible light is emitted at the changed light emission time ratio. And a visible light control method.   The visible light control device includes a light emission time ratio relaxation control step that relaxes a time change rate at a change point of the drive signal generated by the drive signal generation step and emits the visible light at a light emission time ratio of the relaxed drive signal. The visible light control method according to claim 9, wherein: A program to be executed by a computer of a visible light control device that controls blinking of visible light including information,
Modulation processing for modulating a subcarrier and generating a modulated signal;
Based on the modulation signal generated by the modulation process, the visible light control process for controlling the blinking of the visible light and emitting the visible light at a predetermined emission time ratio;
Changing the predetermined light emission time ratio, and causing the computer to execute a light emission time ratio control process for emitting the visible light at the changed light emission time ratio,
The light emission time ratio control process is:
A period modulation signal generation process for generating a period modulation signal for changing the period of the modulation signal generated by the modulation process;
A drive signal generation process for generating a drive signal that is a logical sum of the period modulation signal generated by the period modulation signal generation process and the modulation signal generated by the modulation process;
Based on the drive signal generated by the drive signal generation process, the blinking of the visible light is controlled, the predetermined light emission time ratio is changed, and the visible light is emitted at the changed light emission time ratio. Program.   Cause the computer to execute a light emission time ratio relaxation control process that relaxes the time change rate at the change point of the drive signal generated by the drive signal generation process and emits the visible light at the light emission time ratio of the relaxed drive signal. 12. The program according to claim 11, wherein:

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